package io.zhengqinyu.framework.helper;

import java.sql.Connection;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;

import org.apache.commons.dbcp2.BasicDataSource;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanHandler;
import org.apache.commons.dbutils.handlers.BeanListHandler;
import org.apache.commons.dbutils.handlers.MapListHandler;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import io.zhengqinyu.framework.util.CollectionUtil;

public final class DatabaseHelper {
	private static final Logger LOGGER = LoggerFactory.getLogger(DatabaseHelper.class);

	private static final ThreadLocal<Connection> CONNECTION_HOLDER;

	//the flag for transation
	private static final ThreadLocal<Boolean> FLAG_HOLDER = new ThreadLocal<Boolean>() {
		@Override
		protected Boolean initialValue() {
			return false;
		}
	};

	private static final QueryRunner QUERY_RUNNER;

	// 数据源管理
	private static final BasicDataSource DATA_SOURCE;

	private static final String DRIVER;
	private static final String URL;
	private static final String USERNAME;
	private static final String PASSWORD;

	static {
		CONNECTION_HOLDER = new ThreadLocal<Connection>();
		QUERY_RUNNER = new QueryRunner();
		DRIVER = ConfigHelper.getJdbcDriver();
		URL = ConfigHelper.getJdbcUrl();
		USERNAME = ConfigHelper.getJdbcUserName();
		PASSWORD = ConfigHelper.getJdbcPassword();

		DATA_SOURCE = new BasicDataSource();
		DATA_SOURCE.setDriverClassName(DRIVER);
		DATA_SOURCE.setUrl(URL);
		DATA_SOURCE.setUsername(USERNAME);
		DATA_SOURCE.setPassword(PASSWORD);
	}

	public static void beginTransation() {
		Connection conn = getConnection();
		if (conn != null) {
			try {
				FLAG_HOLDER.set(true);
				conn.setAutoCommit(false);
			} catch (SQLException e) {
				LOGGER.error("begin transation failure", e);
				throw new RuntimeException(e);
			} finally {
				CONNECTION_HOLDER.set(conn);
			}
		}
	}

	public static void commitTransation() {
		Connection conn = CONNECTION_HOLDER.get();
		if (conn != null) {
			try {
				conn.commit();
				conn.close();
			} catch (SQLException e) {
				LOGGER.error("commit transation failure", e);
				throw new RuntimeException(e);
			} finally {
				CONNECTION_HOLDER.remove();
			}
		}
	}

	public static void rollbackTransation() {
		Connection conn = CONNECTION_HOLDER.get();
		if (conn != null) {
			try {
				conn.rollback();
				conn.close();
			} catch (SQLException e) {
				LOGGER.error("rollback transation failure", e);
				throw new RuntimeException(e);
			} finally {
				CONNECTION_HOLDER.remove();
			}
		}
	}

	public static Connection getConnection() {
		Connection conn = CONNECTION_HOLDER.get();
		if (conn == null) {
			try {
				conn = DATA_SOURCE.getConnection();
			} catch (SQLException e) {
				LOGGER.error("get Connection failure", e);
				throw new RuntimeException(e);
			} finally {
				CONNECTION_HOLDER.set(conn);
			}
		}
		return conn;
	}

	public static void closeConnection() {
		if (!FLAG_HOLDER.get()) {
			Connection conn = CONNECTION_HOLDER.get();
			if (conn != null) {
				try {
					conn.close();
				} catch (SQLException e) {
					LOGGER.error("close Connection failure", e);
					throw new RuntimeException(e);
				} finally {
					CONNECTION_HOLDER.remove();
				}
			}
		}
	}

	public static <T> List<T> queryEntityList(Class<T> entityClass, String sql, Object... params) {
		List<T> entityList;
		try {
			Connection conn = getConnection();
			entityList = QUERY_RUNNER.query(conn, sql, new BeanListHandler<T>(entityClass), params);
		} catch (SQLException e) {
			LOGGER.error("query entity list failure", e);
			throw new RuntimeException(e);
		} finally {
			closeConnection();
		}
		return entityList;
	}

	public static <T> T queryEntity(Class<T> entityClass, String sql, Object... params) {
		T entity;
		try {
			Connection conn = getConnection();
			entity = QUERY_RUNNER.query(conn, sql, new BeanHandler<T>(entityClass), params);
		} catch (SQLException e) {
			LOGGER.error("query entity failure", e);
			throw new RuntimeException(e);
		} finally {
			closeConnection();
		}
		return entity;
	}

	public static List<Map<String, Object>> executeQuery(String sql, Object... params) {
		List<Map<String, Object>> result;
		try {
			Connection conn = getConnection();
			result = QUERY_RUNNER.query(conn, sql, new MapListHandler(), params);
		} catch (SQLException e) {
			LOGGER.error("execute query failure", e);
			throw new RuntimeException(e);
		} finally {
			closeConnection();
		}
		return result;
	}

	public static int executeUpdate(String sql, Object... params) {
		int rows = 0;
		try {
			Connection conn = getConnection();
			rows = QUERY_RUNNER.update(conn, sql, params);
		} catch (SQLException e) {
			LOGGER.error("execute update failure", e);
			throw new RuntimeException(e);
		} finally {
			closeConnection();
		}
		return rows;
	}

	public static <T> boolean insertEntity(Class<T> entityClass, Map<String, Object> fieldMap) {
		if (CollectionUtil.isEmpty(fieldMap)) {
			LOGGER.error("can not insert entity: fielf is empty");
			return false;
		}
		String sql = "INSERT INTO " + getTableName(entityClass);
		StringBuilder columns = new StringBuilder(" (");
		StringBuilder values = new StringBuilder(" (");
		for (String fieldName : fieldMap.keySet()) {
			columns.append(fieldName).append(", ");
			values.append("?, ");
		}
		columns.replace(columns.lastIndexOf(", "), columns.length(), ") ");
		values.replace(values.lastIndexOf(", "), values.length(), ") ");
		sql += columns + "VALUES" + values;
		Object[] params = fieldMap.values().toArray();
		return executeUpdate(sql, params) == 1;
	}

	public static <T> boolean updateEntity(Class<T> entityClass, long id, Map<String, Object> fieldMap) {
		if (CollectionUtil.isEmpty(fieldMap)) {
			LOGGER.error("can not update entity: fielf is empty");
			return false;
		}
		String sql = "UPDATE " + getTableName(entityClass) + " SET ";
		StringBuilder columns = new StringBuilder();
		for (String fieldName : fieldMap.keySet()) {
			columns.append(fieldName).append("=?, ");
		}
		sql += columns.substring(0, columns.lastIndexOf(", ")) + "WHERE id=?";
		List<Object> paramList = new ArrayList<Object>();
		paramList.addAll(fieldMap.values());
		paramList.add(id);
		Object[] params = paramList.toArray();
		return executeUpdate(sql, params) == 1;
	}

	public static <T> boolean deleteEntity(Class<T> entityClass, long id) {
		String sql = "DELETE FROM " + getTableName(entityClass) + " WHERE id=?";
		return executeUpdate(sql, id) == 1;
	}

	private static String getTableName(Class<?> entityClass) {
		return entityClass.getSimpleName();
	}
}
